// Test that only data and data-order is important, not the individual operations.
    new EqualsTester()
        .addEqualityGroup(
            hashFunction.hashUnencodedChars("abc"),
            hashFunction.newHasher().putUnencodedChars("abc").hash(),
            hashFunction.newHasher().putUnencodedChars("ab").putUnencodedChars("c").hash(),

    // Test that only data and data-order is important, not the individual operations.
    new EqualsTester()
        .addEqualityGroup(
            hashFunction.hashUnencodedChars("abc"),
            hashFunction.newHasher().putUnencodedChars("abc").hash(),
            hashFunction.newHasher().putUnencodedChars("ab").putUnencodedChars("c").hash(),

    int k1 = mixK1(low);
    int h1 = mixH1(seed, k1);

    k1 = mixK1(high);
    h1 = mixH1(h1, k1);

    return fmix(h1, Longs.BYTES);
  }

  @Override
  public HashCode hashUnencodedChars(CharSequence input) {
    int h1 = seed;

    // step through the CharSequence 2 chars at a time
    for (int i = 1; i < input.length(); i += 2) {
      int k1 = input.charAt(i - 1) | (input.charAt(i) << 16);